Conventional methods for installing a door jamb, window jamb or the like in a building wall or roof have generally involved positioning the jamb in a rough opening and filling the gaps between framing members of the opening and the jamb with wood shims. Properly trimming and installing the shims between the jamb and the frame defining the opening requires a considerable amount of time, skill and effort to properly fit the jamb in the opening so that the jamb is plumb. After the shims have been properly positioned, nails are driven through the jamb and the shims into the supporting framing members defining the opening. Thereafter, protruding pieces of the shims, if any, are cut flush with the edge of the jamb.
It is of course desirable to eliminate the use of shims and to simplify jamb installation. To this end, numerous efforts have been directed toward simplified, shimless jamb mounting systems. While many of these systems have very substantially reduced the amount of time and effort needed to install a jamb in a building panel structure, such as a wall or roof, further improvements are desirable. In particular, it would be desirable to reduce the number of fasteners needed for jamb installation and to provide simpler, easier to manufacture and less expensive jamb mounting brackets, and to provide a jamb mounting assembly that may be at least partially pre-installed on the jamb prior to shipment from the factory.